Antidepressants and Neurodevelopment.

There is no evidence that selective serotonin reuptake inhibitors increase the risk of malformations in babies exposed to these drugs in utero. In 1993 we published a study that did not find an excess of birth defects in the babies of women who took the SSRI fluoxetine (Prozac) or tricyclic antidepressants during pregnancy.

Since that time, there have been other studies, including some metaanalyses, that have not produced evidence that these drugs or the newer SSRIs increase the risk of fetal malformations.

But women are also concerned about how these drugs affect their baby's brain and the neurodevelopment of their children.

We first addressed this issue in a study that compared neurodevelopmental measures in the preschool children of 80 women who had taken a tricyclic antidepressant during pregnancy, 55 women who had taken fluoxetine, and 84 women who had not taken any drug known to have adverse fetal effects. First-trimester exposure to tricyclic antidepressants or fluoxetine had no impact on global IQ, cognitive abilities, or language development in the children, who were assessed between 16 and 86 months. There were also no differences in behavior problems, temperament, mood, activity level, distractibility, or arousability (N. Engl. J. Med. 336:258-62, 1997).

Most of these women had stopped taking the antidepressant after the first trimester, so the study did not address the issue of women who continue treatment throughout pregnancy Unlike the limbs and heart, the brain develops throughout pregnancy, so drugs can theoretically affect brain development later in pregnancy as well.

To complete the picture, we did a prospective blinded study of 46 children whose mothers had taken tricyclics and 40 children whose mothers had taken fluoxetine throughout pregnancy and compared them with 36 unexposed controls. This was the first study to follow the neurodevelopment of children exposed to these drugs throughout pregnancy Children were followed until they were preschool or early school age.

There were no differences in IQ, language development, or temperament between groups after adjusting for factors such as maternal IQ and socioeconomic class, smoking, alcohol use, and the duration and severity of the mother's depression.